Method of sealing glass to aluminum, particularly for electrical feed-through connectors

Abstract

An insulating electrical feed-through connector extending through a wall of aluminium is obtained by using a sintered sleeve comprising phosphate glass in which a conductive pin is inserted. The sleeve is raised to a firing temperature in excess of the dilatometric softening temperature of the vitreous material in the presence of a first effective quantity of alumina between the sleeve and the wall and of a second effective quantity of nickel oxide between the sleeve and the pin, which makes it possible to achieve a simultaneous and direct hermetic sealing of the sleeve to the wall and of the pin to the sleeve.

What is claimed is: 
     
       1. A method of implanting at least one insert into at least one opening in a body of aluminum, or aluminum alloy comprising: a) providing a body of aluminum or aluminum alloy having at least one opening therein, and coating at least a selected portion of said opening in said body with a coating of aluminum oxide of a thickness of 0.5 to 10 microns;   b) providing an insert sintered at least on its periphery which can be inserted into the opening, said sintered periphery comprising sintered phosphate glass powder containing oxygen atoms;   c) inserting said insert into the opening; and   d) heating said insert to a firing temperature greater than the dilatometric softening temperature of said phosphate glass powder with the oxygen atoms of the phosphate glass powder interpenetrating with the aluminum oxide coating hermetically sealing the insert to the body.   
     
     
       2. A method according to claim 1, wherein a binder is added to said phosphate glass powder prior to being sintered. 
     
     
       3. A method according to claim 1, wherein the phosphate glass powder for said insert is prepared as follows: i) preparing the shape of phosphate glass powder;   ii) molding the phosphate glass powder with a binder; and   iii) eliminating the binder.   
     
     
       4. A method according to claim 3, wherein the binder comprises a polycarbonated compound having a chain length of at least 1500 atoms and at most 6000 atoms. 
     
     
       5. A method according to claim 4, wherein the polycarbonated compound is polyethylene glycol 4000 in a quantity of 3% by weight. 
     
     
       6. A method according to claim 1, wherein said sintered phosphate glass powder for said insert has been sintered at about the dilatometric softening point of the phosphate glass powder. 
     
     
       7. A method according to claim 1, wherein the granular size of the phosphate glass powder to be sintered is in excess of 5 microns. 
     
     
       8. A method according to claim 1, wherein the granular size of the phosphate glass powder to be sintered is between about 75 and 106 microns. 
     
     
       9. A method according to claim 1, wherein the phosphate glass powder comprises between approximately 20% and approximately 50% by moles Na 2  O, between approximately 5% and approximately 30% by moles BaO, between approximately 0.5% and approximately 3% by moles Al 2  O 3 , and between approximately 40% and 60% by moles P 2  O 5 . 
     
     
       10. A method according to claim 1, wherein the phosphate glass powder comprises approximately 38.35% by moles Na 2  O, approximately 9.59% by moles BaO, approximately 0.96% by moles Al 2  O 3 , 4.12% by moles of AlN and approximately 42.88% by moles P 2  O 5 . 
     
     
       11. A method according to claim 1, wherein the phosphate glass powder comprises 35% by moles Na 2  O, 8.75% by moles BaO, 0.87% by moles Al 2  O 3 , 3.75% by moles of AlN, 8.75% by moles of B 2  O and 42.88% by moles P 2  O 5 . 
     
     
       12. A method according to claim 1, wherein the phosphate glass powder has added to it an effective quantity of a crystallization modifying agent. 
     
     
       13. A method according to claim 12, wherein the crystallization modifying agent comprises aluminum nitride in a quantity of less than 7% by moles. 
     
     
       14. A method according to claim 12, wherein the crystallization modifying agent comprises aluminum nitride in a quantity of approximately 4.12% by moles. 
     
     
       15. A method according to claim 12, wherein the crystallization modifying agent comprises aluminum nitride in a quantity of approximately 3.75% by moles. 
     
     
       16. A method according to claim 12, wherein the crystallization modifying agent comprises platinum in a quantity of less than 0.5% of moles. 
     
     
       17. A method according to claim 16, wherein the platinum is added as platinum tetrachloride in an amount less than 0.5% by moles. 
     
     
       18. A method according to claim 1, wherein the phosphate glass powder has added to it an effective quantity of an agent for modifying the temperature range at which it may be used. 
     
     
       19. A method according to claim 18, characterized in that the said agent comprises boron trioxide in a quantity of less than 15% moles. 
     
     
       20. A method according to claim 19, wherein the amount of boron trioxide is 8.75% by moles. 
     
     
       21. A method according to claim 1, wherein the phosphate glass powder has a dilatometric softening temperature of between approximately 300° C. and approximately 550° C. and an expansion coefficient between approximately 10 and approximately 25 ppm/°C. 
     
     
       22. A method according to claim 21, wherein the phosphate glass powder comprises approximately 38.35% by moles Na 2  O, approximately 9.59% by moles BaO, approximately 0.96% by moles Al 2  O 3 , 4.12% by moles of AlN and approximately 46.98% by moles P 2  O 5 , and the dilatometric softening temperature is approximately 330° C. and the expansion coefficient is approximately 20 ppm/°C. 
     
     
       23. A method according to claim 1, wherein the phosphate glass powder is sintered at about 335° C. 
     
     
       24. A method according to claim 1, wherein the phosphate glass powder comprises 35% by moles Na 2  O, 8.75% by moles BaO, 0.87% by moles Al 2  O 3 , 3.75% by moles of AlN, 8.75% by moles of B 2  O 3  and 42.88 by moles P 2  O 5 , and the dilatometric softening temperature of the phosphate glass is approximately 475° C. and the coefficient of expansion of the phosphate glass is approximately 16 ppm/°C. 
     
     
       25. A method according to claim 1, further comprising producing the coating of aluminum oxide by chromic anodic oxidation. 
     
     
       26. A method according to claim 1, wherein the thickness of the aluminum oxide coating is between approximately 1 micron and approximately 1.5 micron. 
     
     
       27. A method according to claim 1, wherein the insert of step (b) comprises a metallic element inserted into a sintered sleeve. 
     
     
       28. A method according to claim 27, wherein the aluminum oxide comprises a first metallic oxide and wherein the insert is heated to its firing temperature in the presence of an effective quantity of a second metallic oxide between the sleeve and the metallic element. 
     
     
       29. A method according to claim 27, in which the metallic element is a pin traversing the sleeve from end to end which makes it possible to provide an electrical feed-through connector. 
     
     
       30. A method according to claim 29 wherein portion of said pin extends outside said sleeve, further comprising gilding the portion of the pin outside the sleeve. 
     
     
       31. A method according to claim 27, wherein a metallic element is machined to a desired shape and a coating is applied to at least a portion of a metallic element which is intended to be situated inside the sleeve, said coating comprising a metallic oxide. 
     
     
       32. A method according to claim 31, further comprising: depositing a coating of a filler metal on said portion of the metallic element; and   oxidizing the filler metal in order to form a second metallic oxide.   
     
     
       33. A method according to claim 32, wherein said aluminum oxide comprises a first metallic oxide, the filler metal is nickel, and the coating of nickel deposited on the metallic element is of a thickness of approximately 5 microns, further comprising heating the insert to firing temperature in the presence of said second metallic oxide between the sleeve and the metallic element, the second metallic oxide being a coating of nickel oxide between approximately 2 microns and approximately 5 microns in thickness. 
     
     
       34. A method according to claim 31, wherein the said sintered sleeve is inserted into the opening in the body and the metallic element is inserted into the sintered sleeve. 
     
     
       35. A method according to claim 31, wherein said sleeve comprises a phosphate glass sleeve said sleeve being produced by a process comprising providing a mold having a desired shape, molding the phosphate glass sleeve by pressing phosphate glass powder blended with binder into the mold and thereafter eliminating the binder,   placing the metallic element in said mold to shape a passageway in the sleeve and thereafter fitting the sleeve around the metallic element.   
     
     
       36. A method according to claim 35, wherein the insert is heated to the firing temperature in a neutral atmosphere according to a selected temperature profile. 
     
     
       37. A method according to claim 36, wherein the firing temperature is approximately 450° C. 
     
     
       38. A method according to claim 36 wherein the firing temperature is approximately 525° C. 
     
     
       39. A method according to claim 27, wherein the metallic element comprises a material having a coefficient of expansion of between approximately 15 and approximately 20 ppm/°C. 
     
     
       40. A method according to claim 39, wherein the metallic element comprises a copper-beryllium alloy. 
     
     
       41. A method according to claim 27, wherein said aluminum oxide comprises a first metallic oxide, and further comprising heating the insert to the firing temperature in the presence of a second metallic oxide between the sleeve and the metallic element and said second metallic oxide comprises a coating of nickel oxide on said metallic element. 
     
     
       42. A method according to claim 41, wherein the coating of nickel oxide is between approximately 2 microns and approximately 5 microns in thickness. 
     
     
       43. A method according to claim 1, wherein the opening is a hole extending through the body. 
     
     
       44. A method according to claim 1, wherein after the insert is heated to the firing temperature, the phosphate glass powder is annealed. 
     
     
       45. A method according to claim 1, wherein the body comprises aluminum alloy "5086". 
     
     
       46. A method according to claim 1, in which the body of aluminum or aluminum alloy is a structural element of a device containing at least one electronic circuit. 
     
     
       47. A method according to claim 1 wherein the body of aluminum or aluminum alloy is a structural element of a device containing at least one electronic circuit and the device comprises a bottom and at least one cover of an aluminum based material which is free from copper and of which at least one of said bottom and cover contains silicon, further comprising welding the cover to the bottom by laser welding. 
     
     
       48. A method of implanting at least one insert into an opening in a body of aluminum or aluminum alloy, said opening having an inner surface, comprising: providing a body of aluminum or aluminum alloy having at least one opening therein;   oxidizing the inner surface of said opening in said body to produce a coating of aluminum oxide of a thickness of 0.5 to 10 microns;   preparing an insert of powdered phosphate glass material having a thermal-expansion coefficient between about 10 ppm/°C. and about 25 ppm/°C. and which contains oxygen atoms and is sintered on at least the outer surface thereof;   inserting said phosphate glass insert into said opening in said body; and   heating said insert to a firing temperature greater than the dilatometric softening temperature of said powdered phosphate glass to interpenetrate oxygen atoms in the aluminum oxide coating with the oxygen atoms of the phosphate glass to hermetically seal the insert to body.   
     
     
       49. A method according to claim 48, wherein the entire insert is sintered. 
     
     
       50. A method according to claim 48 wherein said phosphate glass insert has a dilotometric softening temperature of between 300° C. and about 550° C. and an expansion coefficient between about 10 and about 25 ppm/°C. 
     
     
       51. A method according to claim 48 wherein the coating of aluminum oxide has a thickness of 0.5 to about 1.5 microns. 
     
     
       52. A method according to claim 48 wherein said phosphate glass for said insert additionally contains a volatizable binder, and said preparing further comprises pressing said phosphate glass containing said binder to form a shape and heating the insert to a temperature sufficient to sinter at least the outer surface of the insert. 
     
     
       53. A method according to claim 52 wherein said binder comprises a polycarbonated compound. 
     
     
       54. A method according to claim 52 wherein said binder is removed by oven drying prior to said sintering of at least the outer surface of the insert. 
     
     
       55. A method according to claim 49 wherein the phosphate glass for said insert includes a crystallization modifying agent comprising aluminum nitride in an amount less than 7% by moles. 
     
     
       56. A method according to claim 48 wherein the phosphate glass for said insert includes a crystallization modifying agent comprising platinum in an amount less than 0.5% by moles. 
     
     
       57. A method according to claim 48 wherein the phosphate glass for said insert includes an agent for modifying the temperature range in which it can be used. 
     
     
       58. A method according to claim 48 wherein the phosphate glass for said insert contains B 2  O 3  in an amount less than 15% by moles. 
     
     
       59. A method according to claim 48 wherein the phosphate glass for said insert additionally contains at least one material selected from the group consisting of aluminum nitride in an amount less than 7% by moles, platinum in an amount less than 0.5% by moles, Al 2  O 3 , B 2  O 3  in an amount less than 15% by moles, Na 2  CO 3 , BaC 3 , NH 4  H 2  PO 4 , and platinum tetrachloride. 
     
     
       60. A method according to claim 48 wherein the phosphate glass for said insert comprises 35% by moles Na 2  O, 8.75% by moles BaO, 0.87% by mole Al 2  O 3 , 42.88% by moles P 2  O 5 , 3.75% by moles AlN and 8.75% by moles B 2  O 3 . 
     
     
       61. A method according to claim 48 in which the body is a structural element of a box containing at least one electronic circuit. 
     
     
       62. A method according to claim 47 or 48 wherein said sintered phosphate glass powder comprises approximately 20% to 50% by moles of Na 2  O, approximately 5% to 30% by moles of BaO, approximately 0.5% to 3% by moles of Al 2  O 3  and approximately 40% to 60% by moles of P 2  O 5 . 
     
     
       63. A method of implanting at least one insert with a metallic element into an opening in a body of aluminum or aluminum alloy comprising: providing a body of aluminum or aluminum alloy having at least one opening therein, said opening having an inner surface;   oxidizing the inner surface of said opening in said body and coating the oxidized surface in the opening in said body to produce a coating of aluminum oxide of a thickness of 0.5 to 10 microns;   providing an insert in the form of a hollow sleeve of phosphate glass sintered on at least the outer surface thereof, said phosphate glass containing oxygen atoms;   providing a metallic element, a portion of which is sized to be insertable in the hollow sleeve;   depositing a filler metal on the surface of the metallic element on at least the portion thereof which is insertable into said hollow sleeve;   oxidizing the surface of said filler metal;   inserting said metallic element into said sleeve and inserting said sleeve into said opening in said body; and   heating said sleeve and metallic element to a firing temperature greater than the dilatometric softening temperature of said phosphate glass so that oxygen atoms of said phosphate glass interpenetrate with the oxygen atoms in the aluminum oxide coating to hermetically seal the sleeve to the body and the metallic element to the sleeve.   
     
     
       64. A method according to claim 63 wherein the inner surface of the body surrounding the opening is oxidized to produce a coating of aluminum oxide of a thickness of 0.5 to about 1.5 microns. 
     
     
       65. A method according to claim 63 wherein the phosphate glass additionally contains a crystallization modifying agent comprising aluminum nitride in an amount less than 7% by moles. 
     
     
       66. A method according to claim 63 wherein the phosphate glass additionally contains a crystallization modifying agent comprising platinum in an amount less than 0.5% by moles. 
     
     
       67. A method according to claim 63 wherein the phosphate glass additionally contains an agent for modifying the temperature range in which it can be used. 
     
     
       68. A method according to claim 63 wherein the phosphate glass additionally contains B 2  O 3  in an amount less than 15% by moles. 
     
     
       69. A method according to claim 63 wherein the phosphate glass comprises 35% by moles Na 2  O, 8.75% by moles BaO, 0.87% by mole Al 2  O 3 , 42.88% by moles P 2  O 5 , 3.75% by moles AlN and 8.75% by moles B 2  O 3 . 
     
     
       70. A method according to claim 63 wherein the entire insert is sintered. 
     
     
       71. A method according to claim 63 wherein said phosphate glass has a dilatometric softening temperature of between 300° C. and about 550° C. and an expansion coefficient between about 10 and 25 ppm/°C. 
     
     
       72. A method according to claim 63 wherein said metallic element comprises a copper beryllium alloy, said filler metal comprises nickel and the surface of the nickel is oxidized to produce a coating of nickel oxide. 
     
     
       73. A method according to claim 72 wherein said coating of nickel oxide is approximately 2 to 5 microns in thickness. 
     
     
       74. A method according to claim 72 further comprising gilding a portion of said metallic element that is not intended to be inserted into said sleeve. 
     
     
       75. A method according to claim 63 wherein said element is inserted into said sleeve after inserting said sleeve into said body. 
     
     
       76. A method according to claim 63 in which the body is a structural element of a box containing at least one hybrid electronic circuit. 
     
     
       77. A method according to claim 63 wherein said phosphate glass comprises approximately 20% to 50% by moles Na 2  O, approximately 5% to 30% by moles BaO, approximately 0.5% to 3% by moles Al 2  O 3  and approximately 40% to 60% by moles P 2  O 5 . 
     
     
       78. A method of implanting at least one insert into an opening in a body of aluminum or aluminum alloy comprising: providing a body of aluminum or aluminum alloy having at least one opening therein, said opening having an inner surface;   preparing a phosphate glass insert having a thermal expansion coefficient between about 10 ppm/°C. and about 25 ppm/°C., sintered on at least the outer surface thereof;   providing the inner surface of said opening with an aluminum oxide coating have a thickness greater than 0.5 micron;   lodging the insert in said opening; and heating together said body and said insert lodged in said opening to a firing temperature greater than the temperature at which the phosphate glass has a viscosity of about 10 11 .3 poises, to seal the insert to the body.